Fluid lines under high pressure (e.g., pressure vessels and piping systems) are often designed with pressure relief valves to protect the line from dangerous overpressure conditions. These pressure relief valves are generally self-actuated devices set to open when the pressure in the fluid line exceeds a specified level (set-point), allowing fluid to exit the system and thus relieve the overpressure condition. One such example, U.S. Pat. No. 9,677,391, utilizes a valve body having a replaceable disk that ruptures when an overpressure event occurs, allowing fluid to escape to the atmosphere. Another example, U.S. Pat. No. 9,903,493, uses a valve that is forced into the closed position by a buttressing rod. In the event of an overpressure condition in the fluid line, the rod buckles or collapses, opening the valve and allowing fluid to flow through the valve. In both examples, the relief valve is useable only one time, requiring replacement of parts before returning to service, and does not provide a means to quickly reclose the valve when the overpressure condition is resolved.
Certain other examples, such as U.S. Pat. No. 8,281,804, do provide means to reclose the valve when the pressure drops below the set-point, but each suffer from other design shortcomings. For example, each use relief valves that include a ninety (90) degree turn in the fluid flow path directly in communication with the sealing mechanism, and expose one or more sealing faces to abrasive fluid flow. These ninety degree valves typically rely on a mechanical spring arrangement or similarly limited capability with regard to the ease of set-point adjustments. As such, even though they may recluse, they are often unstable in operation, with rapid opening and closing of the closure element as the pressure in the line fluctuates near the pressure set-point (i.e., when the pressure rises to slightly above the set-point and then drops as a result of fluid flowing from the system through the pressure relief valve). Such unstable operation can cause physical damage to components of the pressure relief valve.
Other solutions for pressure relief attempt to electronically control the set-point for a single valve by applying control to a similarly designed ninety degree valve. See for example U.S. Pat. Nos. 3,776,249, 6,283,138, and 9,109,717. However, while they improve upon the ease of user pressure adjustments and set-points, they fail to address the very elementary problem of abrasive slurry erosion on the sealing mechanisms.
Still other solutions seek to utilize industry recognized linear actuated valves that provide seals on the downstream sides of the valves, coupled to single set-point electronic control, but these solutions still fail to remove the sealing face from abrasive fluid flow. Moreover, in industries where the pressure in the conduits is extremely high, such as in the hydraulic fracturing industry, these solutions may also fail to meet industry needs. That is, the valve and actuation means were never intended to be applied to relief valve service.
It should also be noted that the aforementioned electronic control systems have also consistently failed to meet the demands of the dynamic nature of pressurized fluid systems used in the hydraulic fracturing industry, and generally only attempt to monitor pressures in a single fluid conduit. Moreover, these electronic controls do not allow the user to fully integrate the valve controls into their previously established data interpretation methods.
It would be desirable to have a system that can protect single or dual pressurized fluid conduit(s), wherein the conduit(s) can be monitored and relieved of potentially catastrophic overpressures in an independent manner. It would also be desirable to have a system that utilizes valves which provide a linear flow path, and which do not expose sealing surfaces to abrasive fluid flow. Furthermore, it would be desirable to have a system that, by virtue of having two valves applied, may act in an independent manner of redundancy when connected to a single fluid conduit. Still further, it would be desirable to have a system that may be coupled to a single conduit such that a first valve is primarily controlled and a second valve may act as a spare “in the wait” to allow efficient operational use. Still further yet, it would be desirable to have a control system configured to allow a user to define both valve settings independently and integrate valve control into their in-use data management systems.
Therefore, there currently exists a need in the industry for a system that provides effective overpressure relief in a pressurized conduit in a manner that incorporates two independently controlled valves, and which uses components, e.g., valves, sensors, etc., that are isolated or protected from the abrasive fluid flow in the pressurized conduit(s).